SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d45a9f4aa412d13f64572f2729b5ba42766143879e4361466ca511c4693fa2f' 
  AND token = 'U21Arp82uW4xuidqrds2BpuqwOV/Jn61qBN8RPKO9ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}